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Thermal Stability of Specialty Optical Fibers
Andrei A. Stolov, Debra A. Simoff, and Jie Li.
Abstract: Application of silica optical fibers at elevated temperatures is limited by the thermal stability of their polymer coatings, as thermal degradation in most polymer materials occurs at much lower temperatures than silica, which can result in degradation in the fiber performance.
Study of Optical Fiber Damage Under Tight Bend with High Optical Power at 2140 nm
Xiaoguang Sun, Jie Li and Adam Hokansson.
Abstract: Silica optical fibers are being increasingly used for delivering laser power in various medical applications.
All-Fiber Grating-Based Higher Order Mode Dispersion Compensator for Broad-Band Compensation and 1000-km Transmission at 40 Gb/s
S. Ramachandran, B. Mikkelsen, L.C. Cowsar, M.F. Yan, G. Raybon, L. Boivin, M. Fishteyn, W.A. Reed, P.Wisk, D. Brownlow, R.G. Huff and L. Gruner-Nielsen.
Abstract: We use a novel fiber-grating device to demonstrate the first polarization-insensitive all-fiber higher order mode dispersion compensator for broad-band dispersion compensation.
Anomalous Dispersion in a Solid, Silica-Based Fiber
S. Ramachandran, S. Ghalmi, J.W. Nicholson, M.F. Yan, P. Wisk, E. Monberg and F.V. Dimarcello
Abstract: We demonstrate an all-solid (nonholey), silica-based fiber with anomalous dispersion at wavelengths where silica material dispersion is negative.
Light Propagation with Ultralarge Modal Areas in Optical Fibers
S. Ramachandran, J.W. Nicholson, S. Ghalmi, M.F. Yan, P. Wisk, E. Monberg and F.V. Dimarcello
Abstract: We demonstrate robust single-transverse-mode light propagation in higher-order modes of a fiber, with effective area Aeff ranging from 2100 to 3200 µm2.
Bandwidth Control of Long-Period Gratings-Based Mode Converters in Few-Mode Fibers
Siddharth Ramachandran, Zhiyong Wang and Man yan
Abstract: Control of the group-velocity differences between two distinct modes in a few-mode fiber can be used to define the spectral characteristics of long-period gratings written in them.
Band-Selection Filters with Concatenated Long-Period Gratings in Few-Mode Fibers
Siddharth Ramachandran, Samir Ghalmi, Zhiyong Wang and Man Yan
Abstract: We demonstrate a novel device that comprises a pair of broadband and narrowband long-period gratings written in specially designed few-mode fibers to achieve in-fiber bandpass filtering.
Tunable Dispersion Compensators Utilizing Higher Order Mode Fibers
S. Ramachandran, S. Ghalmi, S. Chandrasekhar, I. Ryazansky, M.F. Yan, F.V. Dimarcello, W.A. Reed and P. Wisk
Abstract: We demonstrate a novel tunable dispersion compensator that utilizes higher order mode fibers and switchable fiber gratings.
Record Bandwidth, Spectrally Flat Coupling with Microbend Gratings in Dispersion-Tailored Fibers
Siddharth Ramachandran, Man F. Yan, Eric Monberg, Frank V. Dimarcello, Patrick Wisk and Samir Ghalmi
Abstract: We demonstrate resonant grating couplers with the broadest bandwidth (565 nm) reported to date, using microbend gratings in dispersion-optimized few-mode fibers.
Tunable Optical Fiber Devices Based on Broadband Long-Period Gratings and Pumped Microfluidics
Bharat R. Acharya, Tom Krupenkin, Siddharth Ramachandran, Z. Wang, C.C. Huang and John A. Rogers
Abstract: This letter describes classes of tunable microfluidic fiber (µFF) devices that use specially designed long-period gratings in which the phase matching condition is satisfied over a wide spectral range.
Ultrasensitive Long-Period Fiber Gratings for Broadband Modulators and Sensors
Zhiyong Wang and Siddharth Ramachandran
Abstract: We demonstrate long-period fiber gratings whose attenuation can be changed by 25 dB over a 48-nm spectral band, with ambient-index changes of only 2.7 x 10-4.
Highly Sensitive Optical Response of Optical Fiber Long Period Gratings to Nanometer-Thick Ionic Self-Assembled Multilayers
Zhiyong Wang, J.R. Heflin, Rogers H. Stolen and Siddharth Ramachandran
Abstract: Ionic self-assembled multilayers deposited on long period fiber gratings (LPGs) yield dramatic resonant-wavelength shifts, even with nanometer-thick films.
Lifting Polarization Degeneracy of Modes by Fiber Design: A Platform for Polarization-Insensitive Microbend Fiber Gratings
S. Ramachandran, S. Golowich, M.F. Yan, E. Monberg, F.V. Dimarcello, J. Fleming, S. Ghalmi and P. Wisk
Abstract: Polarization dependence in microbend gratings is an inherent problem, even in perfectly circular fibers, since antisymmetric modes are almost degenerate linear combinations of four distinct, polarization-sensitive modes.
Dispersion-Tailored Few-Mode Fibers: A Versatile Platform for In-Fiber Photonic Devices
S. Ramachandran
Abstract: In-fiber devices enable a vast array of critical photonic functions ranging from signal conditioning (amplification, dispersion control) to network management (add/drop multiplexers, optical monitoring).
High-Energy (Nanojoule) Femtosecond Pulse Delivery with Record Dispersion Higher-Order Mode Fiber
S. Ramachandran, M.F. Yan, J. Jasapara, P. Wisk, S. Ghalmi, E. Monberg, and F.V. Dimarcello
Abstract: Delivery of high peak-power femtosecond pulses with fibers is constrained by nonlinear distortions accumulated during pulse propagation.
Novel Fibers for Ultra-Short and High-Power Pulses
S. Ramachandran, J.W. Nicholson and M.F. Yan
Abstract: Light propagation in higher-order modes of few-mode fibers leads to unique dispersive properties that are challenging or impossible to achieve in conventional fibers.
The Thinnest Optical Waveguide: Experimental Test
M. Sumetsky and Y. Dulashko
Abstract: A thin dielectric waveguide with a subwavelength diameter can exhibit very small transmission loss only if its diameter is greater than a threshold value, while for smaller diameters, waveguide loss grows dramatically.
Optimum Intermediate Fibers for Reducing Interconnection Loss: Exact Solution
Andrew D. Yablon and M. Sumetsky
Abstract: We derive an exact analytical solution for a transmission line of N single-mode intermediate optical fibers that minimize the interconnection loss between any two dissimilar fiber modes that are well described by the paraxial scalar wave equation.
Optics of Tunneling From Adiabatic Nanotapers
M. Sumetsky
Abstract: A theory of light propagation along adiabatic photonic nanowire tapers (nanotapers) having diameters significantly less than the radiation wavelength λ ~ 1µm is developed.
Probing Optical Microfiber Nonuniformities at Nanoscale
M. Sumetsky, Y. Dulashko, J. M. Fini, A. Hale, and J.W. Nicholson
Abstract: We demonstrate a novel, simple, and comprehensive method for probing optical microfiber surface and bulk distortions with subnanometer accuracy.
Propagation of Femtosecond Pulses in Large-Mode-Area, Higher-Order-Mode Fiber
J.W. Nicholson, S. Ramachandran, S. Ghalmi, M.F. Yan, P. Wisk, E. Monberg, and F.V. Dimarcello
Abstract: We demonstrate propagation of 14-nJ femtosecond pulses through a large-mode-area, higher order mode fiber with an effective area of 2100 µm2. The pulses propagate stably in the LP07 mode of the fiber through lengths as long as 12 m.
Effect of Optical Fiber Coating Abrasion on Aging Behavior
Eric A. Lindholm, Rich Heinemann, Brian Slyman, and David Burgess
Abstract: Optical fibers with different protective coatings were abraded then submerged in 50°C water for twenty-eight days. The strength of the abraded and control fibers exposed to zero-stress aging was tracked over time with tensile strength testing. Although the abrasion test represented a severe model of fiber handling, no appreciable strength degradation was detected on the fiber before or after zero-stress aging.
Suppression of Stimulated Raman Scattering in a Cladding Pumped Amplifier with an Yb-doped Filter Fiber
J.M. Fini, M.D. Mermelstein, M.F. Yan, R.T. Bise, A.D. Yablon, P.W. Wisk, and M.J. Andrejco
Abstract: A cladding-pumped, high-power amplifier was built incorporating a star-shaped, Yb-doped filter fiber. Pulsed amplifier measurements demonstrate strong suppression of stimulated Raman scattering accomplished by a special index profile with an up-doped ring.
Raman-Assisted Transmission of 16x10 Gbit/s over 240 km Using Post-Compensation Only
Rasmus Kjær, Michael Galili, Leif K. Oxenløwe, Carsten G. Jørgensen, and Palle Jeppesen
Abstract: We demonstrate transmission of 16 WDM channels at 10 Gbit/s with 50 GHz channel spacing over 3x80 km NZDSF, with small OSNR penalty, using only a single Raman-pumped dispersion compensating module positioned before the receiver.
Increased Pulsed Amplifier Efficiency by Manipulating the Fiber Dopant Distribution
J.M. Oh, C. Headley, M.J. Andrejco, A.D. Yablon, and D.J. DiGiovanni
Abstract: In the pulse application, a significantly increased efficiency of high power large-mode area fiber amplifiers is demonstated by improving the overlap of the doped region with the fundamental mode of the fiber.
Optical Microfibers: Fundamentals and Applications
M. Sumetsky
Abstract: Transmission properties and applications of single-mode optical microfibers are reviewed.
How Thin Can a Microfiber Be and Still Guide Light?
M. Sumetsky
Abstract: For the adiabatically deformed optical fiber the intermode transmission amplitudes and loss vanish exponentially with the characteristic length of the fiber's nonuniformity.
The Microfiber Loop Resonator: Theory, Experiment, and Application
M. Sumetsky, Y. Dulashko, J.M. Fini, A. Hale, and D.J. DiGiovanni
Abstract: This paper describes the theory of a microfiber loop resonator (MLR) and experimentally demonstrates a high quality factor MLR in free space.
Fiber Strength and Reliability
Eric Lindholm and Jie Li
The varied breaking strength of silica fiber can be attributed to the distribution in flaw severity along the fiber length. Micro-cracks can be inherent to the glass itself or a result of the manufacturing process and handling of the fiber. Fiber strength also degrades with time due to fatigue as a result of crack growth accelerated by interaction with moisture.
Advanced Topics on Erbium Doped Fibers for High Performance Amplifiers
B.S. Wang, M.J. Andrejco
Erbium doped fiber amplifiers have been widely deployed for signal amplification in optical transmission systems. High performance amplifiers require erbium doped fiber with high power conversion efficiency and consistent flat gain spectrum. In addition, all impairments associated with EDF must be under good control. This paper reviews the current status and recent progress on erbium doped fibers, illustrates C and L-band spectral characteristics resulting from different doping compositions, presents some approaches for efficient high power amplifiers, and discusses some EDF nonlinear effects with examples.
Bending Induced PMD in Spun Erbium Doped Fiber
Peter Borg Gaarde, Tommy Geisler, Poul Kristensen and Bera Pálsdóttir
We have measured the DGD induced by bending in both active and passive Erbium Doped Fibers. We demonstrate, both theoretically and experimentally, non-trivial behavior of PMD in spun Erbium Doped Fiber (EDF) when coiled to small diameters.
Investigation of New Erbium Doped Fiber Design with Improved Splicing Performance
Torben Veng and Bera Pálsdóttir
An erbium doped fiber (EDF) having a new type of refractive index profile, useful for optimizing fusion splicing abilities, is studied with respect to splice performance and gain characteristics.
Novel Erbium Doped Fiber for High Power Applications
B.S. Wang, G. Puc, M. Andrejco
A novel erbium doped fiber (EDF) designed for high power WDM applications is presented. The fiber design and performance versus numerical aperture and cutoff wavelength are described based on an advanced EDFA simulation model. The optical and spectral characteristics of the high power fiber are shown. Experimental measurement results of this fiber and comparison with typical commercially available EDFs are given. Performance results show that the new EDF is ideal for high power EDFA applications. It features high power conversion efficiency at high pump power, especially with 980 nm pumping, extremely flat gain shape, very low splice loss to typical pigtail fibers, and negligible macro-bending loss.
Erbium-Doped Fiber Design for Improved Splicing Performance
Torben Veng and Bera Pálsdóttir
Fusion splicing is a well-known technique to connect a fiber pair and fusion splicers have been commercially available for this process for a long time. An important feature of a fusion splice is the coupling loss that is influenced by - among other things - the mutual spotsizes of the two fibers involved. Hence, similiar fibers such as standard single mode fibers can be spliced to nearly zero loss whereas dissimiliar fiber pairs may give higher loss. The latter category covers the splice combinations of erbium doped fibers that are often spliced to other fiber types such as the standard single mode fiber.
Characterization of Gain Spectral Variation of Erbium-Doped Fibers Codoped with Aluminum
B.S. Wang, G. Puc, R. Osnato, B. Pálsdóttir
Characteristics of gain spectral variation of EDFs and its dependence on aluminum doping level and fiber mode design are quantitatively studied. Based on experimental data and manufactured fibers with different aluminum levels, the correlation between aluminum concentration and both absorption spectrum and gain flatness is revealed. Gain spectral variation for over a million meters of EDFs manufactured in last several years is presented. The result shows that peak-to-peak spectral shape variation for all these fibers are within 0.8% in a 36 nm C-band window.
Silica Based Erbium Doped Fiber Extending the L-band to 1620+ nm
Inger Pihl Byriel, Bera Pálsdóttir, Matt Andrejco, C. Christian Larsen
A fiber has been developed for use in extended L-band amplifiers, utilizing the wavelength range from 1565 to 1620 nm. The fiber is silica based and has low splice loss to standard telecommunication fiber. The quantum conversion efficiency is >60%.
Optimization of Fusion Splice Process for High Numerical Aperture Coupler Fiber and Erbium Doped Fiber
Honggu Jiang, Timothy McMahon, Jie Li
Fusion splicing erbium doped fiber (EDF) to other single mode fibers has become more critical as the required overall insertion loss for erbium doped fiber amplifiers (EDFA) has significantly decreased in the last few years. In this paper, we describe and discuss an approach to developing a low loss splice method for fusion splicing high numerical aperture (NA) 980/1600 wavelength-division-multiplexing (WDM) coupler fiber and EDF. The results indicate that the fiber end preparation before the fusion is especially critical for obtaining a low loss splice for the fiber pair.
Strength and Reliability of Silica Optical Fibers in Automotive Communication Networks
Eric A. Lindholm, Edward Warych & Daniel Whelan
Abstract: Demand for new safety, sensor, control, information and entertainment technologies in automobiles is stretching the data rate limits of communication networks using conventional wiring and plastic-based fibers. Thus far, the switch to high-bandwidth glass optical fibers has been hindered by concerns about the fiber's reliability. In this study, we present zero-stress aging data for glass optical fibers with different protective coatings exposed to environmental conditions relevant to the automotive industry.
Aging Behavior of Optical Fibers in Aqueous Environments
Eric A. Lindholm, Jie Li, Adam Hokansson, Brian Slyman, and David Burgess
Abstract: Silica optical fibers drawn from a common preform and coated with specialty coatings were exposed to zero-stress aging in various aqueous environments for approximately ten months. The strength of the fiber samples was tracked with two-point bend testing. The onset of an aging “knee” was observed for some fiber samples while other coatings offered enhanced protection from the effects of moisture-induced strength degradation.
Advances In Design and Development of Optical Fibers for Harsh Environments
Jie Li, Eric A. Lindholm, Jana Horska, and Jaroslaw Abramczyk
Abstract: Optical fiber for harsh environments presents unique design challenges, particularly in coatings required to maintain the properties of the fiber. In a typical harsh environment application, the optical fibers are exposed to water, hydrogen or other harmful chemicals at elevated temperatures, e.g. > 200 °C. The fibers are commonly coated with a thin layer of carbon and further coated with thermosetting polyimide materials that can withstand significantly higher temperature than the common UV cured acrylate coatings. In this paper, we describe our recent efforts in understanding the impact of the environment on the fiber performance and report the advances in improving fiber and coating design to minimize the impact. Along with the discussion of the familiar fiber failure mechanisms, we also show the existence of a unique failure mechanism, i. e. the degradation of coating properties that leads to optical transmission loss.
Low Speed Carbon Deposition Process for Hermetic Optical Fibers
Eric A. Lindholm, Jie Li, Adam S. Hokansson, Jaroslaw Abramczyk
Abstract: For optical fibers used in adverse environments, a carbon coating is frequently deposited on the fiber surface to prevent water and hydrogen ingression that lead respectively to strength degradation through fatigue and hydrogen-induced attenuation. The deposition of a hermetic carbon coating onto an optical fiber during the draw process holds a particular challenge when thermallycured specialty coatings are subsequently applied because of the slower drawing rate. In this paper, we report on our efforts to improve the low-speed carbon deposition process by altering the composition and concentration of hydrocarbon precursor gases. The resulting carbon layers have been analyzed for electrical resistance, Raman spectra, coating thickness, and surface roughness, then compared to strength data and dynamic fatigue behavior.
Zero-Stress Aging Behavior of Optical Fibers with Various Protective Coatings
Eric A. Lindholm, Jie Li, Adam Hokansson, Brian Slyman & David Burgess
Abstract: Optical fibers with various coatings are subjected to zero-stress soaking in water at room temperature and at 80°C. Change in fiber strength over time is tracked using two-point bend strength testing. The aging behavior of the fibers with different coatings is compared and the results are discussed.
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